Commercial signs and awnings are more structurally complex than they appear. A freestanding pylon sign must withstand wind forces that can exceed thousands of pounds of lateral load. A cantilevered awning attached to a building facade concentrates significant force at its anchor points. Most jurisdictions require PE-stamped structural engineering for signs and awnings above basic size thresholds as part of the sign permit process. Our specialty structure engineering covers signs, awnings, and canopies for commercial clients in all 50 states.
When PE Engineering Is Required for Signs
The threshold for required engineering varies by jurisdiction, but the general pattern is that large signs, high signs, and any sign attached to a structure require engineering. Common thresholds that trigger engineering requirements include signs with a face area exceeding 32 to 100 square feet depending on jurisdiction, pole or pylon signs exceeding 6 feet in height, electronic message center signs due to their structural complexity, and any sign on a building that exceeds the weight or area threshold specified in the local sign code.
High-wind regions such as coastal Florida, the Gulf Coast, and hurricane-prone areas typically have stricter requirements because wind loads on signs in these regions are substantially higher than in other parts of the country. A sign that would not require engineering in an inland location may require full PE engineering in a coastal high-wind zone.
Seismic zones also trigger additional engineering requirements. Signs in high-seismic areas must be designed to resist earthquake-induced lateral forces in addition to wind loads. The combined wind and seismic design creates more complex loading conditions that require careful analysis. Our engineering team is familiar with ASCE 7 provisions for both wind and seismic sign design in every region of the country.
What Engineers Calculate for Signs
Wind Load Analysis
Wind load on a sign follows ASCE 7 Chapter 29, which provides design procedures for freestanding walls and signs. The calculation starts with the basic wind speed for the project location (from ASCE 7 wind speed maps) and applies factors for exposure category, height above ground, and the sign’s solid ratio. Solid signs with no openings experience higher wind loads than open lattice signs because wind passes through open signs rather than deflecting entirely around them.
For a large solid sign, the resulting wind force can be substantial. A 10-foot by 20-foot solid sign in a high-wind coastal location may experience 15,000 pounds or more of wind force at the design wind speed. The structural system must carry this force from the sign face through the support structure and into the foundation.
Foundation Design for Pole Signs
Freestanding pole and pylon signs are supported on concrete foundations that must resist the overturning moment from wind. The overturning moment equals the wind force times the height from the ground to the center of wind force application. For a tall sign, this moment is large. Concrete caisson foundations for commercial signs commonly range from 18 to 36 inches in diameter and 8 to 15 feet in depth depending on the sign size, height, and local soil conditions.
When Engineering Is Required for Awnings
Awnings attached to commercial building facades require engineering in most jurisdictions when they exceed basic size thresholds or when they are of non-standard construction. Frame awnings with metal tubing frames, large canvas or polycarbonate awnings, and awnings that project significant distances from the building all require engineering review. The structural specialty structures engineering for an awning covers both the awning structure itself and the connection to the building.
The connection to the building is often the critical element. An awning exerts downward load from self-weight plus snow and live load, and uplift from wind on its underside. The connection must transfer all of these forces into the building’s structural framing without overstressing the existing framing members at the connection points.
What the Permit Package Includes for a Sign
A sign permit package with structural engineering typically includes a site plan showing the sign location, an elevation drawing showing the sign dimensions and height, structural drawings showing the support structure and foundation, a structural calculations summary, and the PE’s stamp and signature on all engineering documents. Some jurisdictions also require an electrical permit for illuminated signs, which is separate from the structural engineering.
Frequently Asked Questions
Does a vinyl banner or temporary sign require engineering?
Temporary signs, banners attached to buildings with standard hardware, and very small signs typically do not require engineering or permits. However, large temporary banners attached to high structures, and any temporary sign that could cause injury if it fell, should be reviewed for adequacy even if not technically required by code.
Can the same engineer stamp both the sign structure and the building attachment?
Yes. When the sign or awning is attached to a building, the engineer designs both the sign structure and the wall anchorage as a complete system. This integrated design ensures that the loads from the sign are properly distributed into the building structure.
How long does sign structural engineering take?
For a standard commercial pole sign or building-mounted sign, structural engineering typically takes three to five business days. Large or complex signs with unusual geometry may take longer. We prioritize sign engineering for clients with tight permit timelines.
Start Your Sign or Awning Engineering
We provide PE-stamped structural engineering for signs, awnings, and specialty structures in all 50 states. Submit at rightangleeng.com/get-started.
References
American Society of Civil Engineers. (2022). ASCE 7-22: Chapter 29: Wind Loads on Building Appurtenances and Other Structures. Reston, VA.
International Building Code. (2021). Chapter 16: Structural Design; Chapter 33: Safeguards During Construction. ICC.
Sign Research Foundation. (2020). Sign Engineering: A Technical Reference for Sign Professionals.